Interesting post Rand. I think supplementing a larger link builiding strategy with article marketing is fine in the short term as it can give an immediate lift.

The problem as you point out is that many SEO's completely rely on article marketing for their link building. As a result their creative portfolios look terrible. I'm fine with this as it saves the more interesting, creative accounts for those of us that want to do interesting and creative work.

Maybe another way of pushing your point is this.

If SEO businesses want to be taken seriously with the client, be more involved in marketing and brand strategy. Or pitch for and win big, blue chip multi-national, multi-lingual clients on a regular basis. THEY NEED TO GET SERIOUS WITH CONTENT STRATEGY.

It's time to look outside of spammy, easy to do, small effect strategies and create content that real websites would love to publish.

It's interesting but maybe you are looking for the wrong thing here. What Google has admitted to is assessing the authority of the person sharing the information. Having a lot of shares increases the probability of people with influence sharing the page.

It might be worth using a buzz monitoring tool like sysomos to assess the people who have passed the content on and then run a correllation on some clever maths around the combined influence of the crowd.